The present invention, referred to as optoelectronic probe, concerns a novel apparatus and method for characterization and micromanipulation of particles or biomolecules in an electrolyte solution. Electric fields, which include both time constant and time-varying components, are applied to a thin insulating layer covered, lightly doped semiconductor material. Illumination injects carriers into the insulator/semiconductor interface to compensate the leaking minority carrier current and maintain an inversion layer, which works as an electrode to control the particle movements. A particle array, or even a single cell, can be assembled in, or moved along with the inversion layer electrode, which is induced by illumination. Furthermore, an impedance analyzer is utilized to characterize the trapped particles, or single cell. The present invention has numerous uses, such as bio-chemical analysis systems, and nanosize structures assembly for electronic or optical devices.